Disaccharide analysis of human skin glycosaminoglycans in sun-exposed and sun-protected skin of aged people

The negative conduction effect of quinidine on each of the successive phases of the ventricular depolarization was investigated using an original noninvasive method: the spatial velocity electrocardiogram of the QRS complex (SVECG-QRS). We performed a randomized placebo-controlled trial in 10 healthy subjects with a single oral dose of quinidine (330 mg) or placebo. Electrocardiographic acquisition and processing (220 recordings for the complete trial) were performed using the Lyon vectorcardiographic program. For each SVECG-QRS curve, the position of seven specific points from A (onset of QRS) to G (end of QRS) were determined precisely. The six successive time intervals between these points (AB-FG) and five velocity values (B-F) were then calculated. The QRS complex was longer under quinidine than placebo (102.4 +/- 1.6 vs. 100.3 +/- 1.5 ms). The difference was at the periphery of statistical significance (p = 0.05), and this lack of statistical difference may be mainly due to the low serum levels of quinidine obtained at the peak of the concentration (1.46 +/- 0.4 mg/1). All six QRS time intervals were longer under quinidine, but only the BC interval was significantly different (9.3 +/- 1.1 vs. 18.8 +/- 1.1 ms; p < 0.05) suggesting a more pronounced negative conduction effect at the onset of ventricular depolarization. No significant modifications were observed for the velocity values. We conclude that (1) the negative conduction effect of quinidine is heterogeneous, but a further study with a higher dose of quinidine (concentration-dependent effect) is required to confirm this hypothesis and (2) the spatial velocity electrocardiogram of the QRS complex allows a detailed analysis of the ventricular conduction phases. The results of the measurement were found to be reproducible. This noninvasive tool could be used in clinical practice to assess effects of antiarrhythmic drugs on successive ventricular depolarization phases.     

Texture analysis by electron diffraction

Electron diffraction methods for the determination of individual grain orientations and selected area diffraction (SAD) pole figures are briefly reviewed. The standard techniques of orientation determination grain-by-grain are the interpretation of selected-area electron spot and microbeam Kikuchi diffraction patterns with a transmission electron microscope (TEM). Electron-transparent thin samples are required. Specimen areas smaller than 500 nm or 10 nm in diameter, respectively, can be studied. Alternatively, selected area pole figures can be measured on a TEM. This technique is similar to the conventional transmission x-ray method. The orientations of grains in a bulk sample are obtained with a scanning electron microscope (SEM) from back-reflection Kikuchi patterns (i.e. electron backscattering patterns) or from channelling patterns. Spatial resolution is approximately 1 μn or 5 μm, respectively. Individual grain orientation and pole figure measurements can be performed on-line by interfacing the electron microscope with a computer. Outstanding advantages of texture measurement by electron microscopy over x-ray and neutron diffraction are the ability to image the microstructure of the sampled area which complements texture measurement, and the high spatial resolution in diffraction and imaging modes. Experimental results of individual grain orientation measurement may be represented by inverse pole figures, orientation distribution functions, and misorientation distribution functions.     

Aspects on the physiology of human skin: studies using particle probe analysis

Near-infrared (NIR) spectroscopy is an inexpensive and noninvasive optical method to characterize biologic and physiologic systems. Measurements of oxygen saturation in various organs, cytochrome oxidase concentration, and glucose concentration in tissue are examples of NIR spectroscopy applications. This instrument also has potential for diagnostic imaging by comparing the optical properties of a given point in tissue with those of the surrounding areas, e.g., tumor localization, hematoma detection, or deep vein thrombosis detection. Currently, NIR spectroscopy is available in three modalities: time-resolved spectroscopy (TRS), continuous-wave spectroscopy (CWS), and a phase-modulation device. This paper describes a single-source phase-modulation device and a multiple-source (in- and anti-phased) device and their application to system identification. The phase and intensity information for homogeneous systems is correlated with system and instrumental parameters. Phase and intensity changes resulting from the presence of one and two absorbers are illustrated. The sensitivity of in- and anti-phased phase-modulation devices (phased arrays) is demonstrated. The use of amplitude-modulated phased array for heterogeneity detection is described.     

A system of measuring surface relief and elasticity of the skin

An opticoelectronic system for measurement of a surface microprofile and elasticity of the skin in real time has been developed operating with a source of radiation having small time coherence. The frequency of measurement is 120 Hz, accuracy at least 3 microns. The system can be used for anthropological inspections, study of age and pathological changes in the skin.     

Molecular analysis and comparison of radiation-induced large deletions of the HPRT locus in primary human skin fibroblasts

Genetic alterations in gamma-ray- and alpha-particle-induced HPRT mutants were examined by multiplex polymerase chain reaction (PCR) analysis. A total of 39-63% of gamma-ray-induced and 31-57% of alpha-particle-induced mutants had partial or total deletions of the HPRT gene. The proportion of these deletion events was dependent on radiation dose, and at the resolution limits employed there were no significant differences between the spectra induced by equitoxic doses of alpha particles (0.2-0.4 Gy) and gamma rays (3 Gy). The molecular nature of the deletions was analyzed by the use of sequence tagged site (STS) primers and PCR amplification as a "probe" for specific regions of the human X chromosome within the Xq26 region. These STSs were closely linked and spanned regions approximately 1.7 Mbp from the telomeric side and 1.7 Mbp from the centromeric side of the HPRT gene. These markers include: DXS53, 299R, DXS79, yH3L, 3/19, PR1, PR25, H2, yH3R, 1/44, 1/67, 1/1, DXS86, D8C6, DXS10 and DXS144. STS analyses indicated that the maximum size of total deletions in radiation-induced HPRT mutants can be greater than 2.7 Mbp and deletion size appears to be dependent on radiation dose. There were no apparent differences in the sizes of the deletions induced by alpha particles or gamma rays. On the other hand, deletions containing portions of the HPRT gene were observed to be 800 kbp or less, and the pattern of the partial deletion induced by alpha particles appeared to be different from that induced by gamma rays.     

Immunity at the surface: homeostatic mechanisms of the skin immune system

The coordinated function of multiple epidermal and dermal cell populations allows the skin immune system to respond rapidly and effectively to a wide variety of insults occurring at the interface of the organism and its environment. Keratinocytes are the first line of defense in the skin immune system, and keratinocyte-derived cytokines are pivotal in mobilizing leukocytes from blood and signaling other cutaneous cells. Cytokine-mediated cellular communication also enables dermal fibroblasts and endothelial cells lining the cutaneous vasculature to participate in immune and inflammatory responses. Skin is an important site for antigen presentation, and both epidermal Langerhans cells and dermal dendritic cells play pivotal roles in T cell-mediated immune responses to antigens encountered in skin. Proinflammatory signaling pathways are necessarily balanced by a variety of regulatory pathways that help maintain the homeostatic functioning of the skin immune system.     

The time-related expression of p53 protein in human skin wounds--a quantitative immunohistochemical analysis

Failure to acknowledge ways of knowing in nursing education curricula other than linear reasoning hinders the development of the full extent of mental abilities brought to learning situations by nursing students. Nurse educators are challenged to develop creative methods to facilitate nursing students' intuitive thinking. In this article, a teaching strategy is described in which graduate students' exemplars of intuition in clinical practice are shared with undergraduate nursing students. Implications of using this teaching approach to demystify the intuitive process and address its legitimacy are discussed.     

Thermometry of the surface of human skin. A study on a model using thermocouples, thermistors, thermovision and thermodyes

The temperature of the surface of a model of human skin is measured using a recently developed probe to house a thermocouple or thermistor. The results are compared with thermovision and thermodye measurements. The effect on skin temperature of hot and cold vessels at various depths is investigated.     

Texture analysis of sonographic features of the parotid gland in Sj?gren's syndrome

OBJECTIVE: The purpose of this study was to develop a method for quantitative analysis of the sonographic features of parotid glands as a noninvasive tool for the diagnosis of Sj?gren's syndrome. SUBJECTS AND METHODS: Sonographic texture analyses were performed on the parotid glands of 44 patients with Sj?gren's syndrome, 83 healthy volunteers, and 17 patients with chronic parotitis, using a fast Fourier transform program. RESULTS: Texture analysis of sonographic studies of the parotid gland using a Fourier transform showed that the sum of the normalized radial power spectrum in the low-spatial-frequency region (S value) of the parotid gland was significantly higher (p < .0001) in the patients with definite Sj?gren's syndrome [6.70 +/- 2.13 (x10(5))] than in the 72 age-matched normal volunteers [3.25 +/- 1.08 (x10(5))]. However, patients with probable Sj?gren's syndrome showed S values [3.92 +/- 1.88 (x10(5))] similar to those of the controls. On the other hand, SDs of the echo levels in the parotid gland showed significantly greater (p < .0001) values in patients with definite (4.63 1.07) and probable (4.53 1.47) Sj?gren's syndrome than in the normal controls (3.30 0.76). Discriminant analysis showed that a combination of these two distinctive values increased diagnostic accuracy to 96.9%. Furthermore, S values and SDs correlated well with the qualitative grading of sonographic features and with the gradings of sialography. CONCLUSION: The system we describe for texture analysis of sonographic images is useful in the diagnosis of Sj?gren's syndrome.     

Characterization of electric-pulse-induced permeabilization of porcine skin using surface electrodes

We measured the transient and long-term changes of permeability of full-thickness porcine skin after the application of a single or a train of electric pulses, as the basis for optimization of the electrical parameters for enhancing transdermal drug or gene delivery by electroporation. Two electrodes were attached to the stratum corneum of excised skin for transdermal electric pulse delivery and impedance measurement. Both transient and long-term permeabilization were found to be dependent on the electrical exposure dose, i.e., the product of pulse voltage and cumulative pulsing (exposure) time. Skin resistance dropped to about 20% of its prepulsing value when pulsed beyond a critical dosage of 0.4 V-s (with 20-40 V across each skin path), but recovered rapidly within seconds after the pulse. Long-term permeabilization of the skin required repeated pulsing with a minimum potential of 160 V (80 V across each skin path). The maximum long-term resistance drop, to 35% of the initial value, required a dose greater than 200 V-s, recovering slowly and seldom completely in tens of minutes to hours. The decrease and recovery of the resistance were dependent on the frequency and pulse length only for low-dose electrical exposure.     

Reproducibility of the vascular response to heating in human skin

Blood flow in human skin increases enormously in response to direct heating. If local skin temperature is held above 42 degrees C, blood flow eventually stabilizes at a level beyond which other influences, barring change in blood pressure, can produce no further increase. If this maximal level is a reproducible characteristic of an individual's cutaneous vasculature, it could be useful in comparing individuals; for example, in their response to hyperthermia. Our experiments were carried out to discover whether the maximal response of the vasculature of the skin of the forearm can be reproduced within reasonable limits and, also, to clarify the time course of the response. We used water sprayed over the surface of the forearms of 10 subjects to hold skin temperature above 42 degrees C for 60 min. During the last 10 min of heating, forearm blood flow (via venous occlusion plethysmography) was stable, at a level ranging from 16 to 38 ml.min-1.100 ml-1. This level, normalized to a blood pressure of 100 mmHg, was reproduced in a given individual on four or five occasions, with an average coefficient of variation of 10%. The response was 77 +/- 11% (SD) complete after 20 min of heating. Elapsed time at 90% of the final value was 35 +/- 9 (SD) min. We conclude that the maximal forearm blood flow response to local heating is a reproducible characteristic of the cutaneous vasculature with potential utility in the scaling of responses between and within individuals.     

Membrane proteins in human skin tumors

The microsomal, mitochondrial, and nuclear fractions of cutaneous tumors have been investigated. Cutaneous tumors were homogenized and microsomal, mitochondrial, and nuclear fractions were purified. The membrane proteins were solubilized with sodium duodecyl sulfate (SDS). The membrane lipids were removed and membrane proteins were solubilized again in a small volume of SDS solution and chromatographed in SDS-acrylamide slab-gel. The plates were stained with Coomassie Brilliant Blue to show protein bands. The preliminary results show that the electrophoretic profiles of microsomal proteins are characteristic of some tumors.     

Determination of the temperature of thermosensitive spots of the human skin]

The ETV6 (TEL) locus at chromosome band 12p 13 is a major site of translocations in acute leukemia, particularly in childhood acute lymphoblastic leukemia (ALL). In cases with translocations involving ETV6, the normal ETV6 allele is often deleted. In addition, loss of heterozygosity of ETV6 is frequently observed in childhood'ALL. Thus, it has been suggested that ETV6 may have an anti-oncogenic role to play, in addition to its oncogenic role. We have described an unusual case of ALL in which ETV6 is found fused to the ABL gene; ABL is normally activated by fusion to the BCR gene in the 9:22 translocation. We expanded the primary cells from this ETV6/ABL rearranged case of ALL in SCID animals and analyzed them for expression of both ETV6/ABL and the normal ETV6 mRNA. We found that both the rearranged and normal ETV6 mRNAs are expressed in the expanded cell population. Furthermore, sequence analysis of the ETV6 PCR product revealed no point mutations which would influence the amino acid sequence. Thus, deletion of the second ETV6 allele is not necessary for the transformation to leukemia by ETV6/ABL.     

Use of the Fourier series window protocol with a zig-zag surface coil in 31P NMR human skin spectroscopy. A theoretical study

The use of a zig-zag surface coil with a three-pulse Fourier Series Window (FSW) has been suggested as a means by which in vivo NMR spectroscopic studies of human skin can be performed. Using direct numerical simulations of the magnetic field profile of a 10 limb zig-zag surface coil, the role of the FSW in reducing NMR signals originating from the deeper skeletal muscle layers is examined theoretically. The extent of muscle signal contamination is determined for different coil inter-limb spacings and pulse width settings. The optimum inter-limb spacing for studying living human skin, that which minimizes signal contamination and maximizes skin signal collected, is shown to be between 4 and 6 mm. These calculations demonstrate that the FSW and zig-zag surface coil offer a protocol for investigating the metabolism of large areas of surface tissue while keeping signal contamination from the deeper skeletal muscle layers down to an acceptable level.     

Adrenoleucodystrophy: dermatological findings and skin surface lipid study

Co(II), Ni(II), Cu(II) and Zn(II) complexes of levamisole (LMS) were prepared and characterized by elemental analyses, IR spectroscopy, 1H and 13C NMR and mass spectrometry. The following general formula was derived: M(LMS)2Cl2, where M = Co, Ni, Cu, Zn. It was established that LMS behaved as a monodentate ligand and the coordination was accomplished through the N-7 atom. The toxicity and the immunomodulating activity of the complexes on mice and rats in comparison with uncomplexed LMS was assayed. The metals in the complexes exerted different changes in the toxicity of LMS. The complex containing Zn(II) was less toxic and manifested higher immunomodulating activity than LMS.